This study is a randomized, multi-center, double-blind clinical trial to assess safety and effectiveness of Modafinil in treatment of fatigue in multiple sclerosis. The objectives of this study will be tested using the Fatigue Severity Scale, Modified Fatigue Impact Scale (MFIS), Visual Analogue Fatigue scale, actigraphy scores, Short Form 12, Epworth Sleepiness Scale, Kurtzke EDSS, and the Depression Scale.